True Coincidence Summing Correction in Gamma Spectroscopy

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COI g N p, g = (3.13) N' p, g And therefore, from Equation (3.12), the overall correction factor is given by, COI g = n ∑ ε . n g ε g, i COI i= 1 g, i (3.14) For an infinitesimally small subsource volume, the summation in equation (3.14) can be replaced by volume integration COI g = ∫∫∫ V ε COI ε g g,( xyz) g,( xyz) dxdydz (3.15) where ∫∫∫ ε = ε dxdydz (3.16) g V g,( xyz) For each subsource of the voluminous source, the peak efficiency ε g,i is calculated using Canberra LabSOCS methodology. This method implies mathematical techniques for the full energy peak efficiency computation of a Germanium detector for any source geometry. LabSOCS calibration software is an option of the application software packages available for Gene 2000 spectroscopy platform. Genie 2000 program is efficiency-curved based, used in the Landesmessstelle für Radioaktivität Bremen for environmental and low-level γ-ray spectrometry. 3.5 Overview of Genie 2000 Gamma Analysis Software Genie 2000 possess a set of capabilities for spectral analysis and acquisition from Multichannel Analyzers (MCAs). It performs MCA control, spectral display and manipulation, basic spectrum analysis and reporting. Moreover it has options for 41
comprehensive spectrum analysis for alpha and gamma spectroscopy and quality assurance. Genie 2000 Basic Spectroscopy Software Description For data acquisition, display and analysis in personal computers, Genie 2000 Basic Spectroscopy Software (S500) is a multipurpose environment, which is capable to run various independent count procedures for several detectors simultaneously. It has designed-in network support for remote and multiple accesses to acquisition hardware and other resources. Figure 3.2 Diagram of Multiple Genie 2000 Network.[14] Spectral Analysis The Genie 2000 Basic Spectroscopy Software has a set of manually executable base spectroscopic analysis algorithms. These analysis of a spectrum is illustrated below using the following steps: Complete Calibration Functions. There are several options for energy (including low-tail and FWHM values) and efficiency calibration and a peak to total calibration can be implied for cascade summing of coincident peaks, these calibrations can be graphically displayed. Calibrations were done in conjunction with displaying the spectrum in Spectroscopy window. A certificate file (containing energies associated with the nuclide in the standard) was loaded, then energy was selected and after this the peak was selected directly from the spectral display. 42
Page 1 and 2: Universität Bremen Faculty of Envi
Page 3 and 4: 2.2 The Origin of Summing 19 2.3 Su
Page 5 and 6: Acknowledgements My recognition to
Page 7 and 8: List of Figures: Figure 1.1 - Compa
Page 9 and 10: List of Tables: Table 1.1 - Typical
Page 11 and 12: the photopeak area is related to el
Page 13 and 14: Figure 1.1 Comparative pulse height
Page 15 and 16: 1.4.2 Packing of the Detector HPGe
Page 17 and 18: Table 1.1 Typical FWHM values as a
Page 19 and 20: The gamma photons produce electron-
Page 21 and 22: Figure 1.7 Peak and background area
Page 23 and 24: • Absolute full-peak energy effic
Page 25 and 26: p c =1-e -2Rτ (1.6) R is the mean
Page 27 and 28: amplifier output pulses shapes are
Page 29 and 30: Figure 2.3 Simplified decay scheme
Page 31 and 32: Counts 5000 4000 3000 2000 1000 Eu-
Page 33 and 34: Figure 2.6 Ratio of count rates in
Page 35 and 36: participate in summing. However, ca
Page 37 and 38: Figure 2.8 The efficiency curve con
Page 39 and 40: The above discussion leads to the c
Page 41 and 42: The ratio n 2 /n’ 2 would be used
Page 43 and 44: • The larger Eu-152 factors for t
Page 45 and 46: As discussed in chapter 2, the emis
Page 47 and 48: ∫ ∫ ε r) ε t ( r) dV ( r) dV
Page 49: For equation (3.8); N p,g = measure
Page 53 and 54: Tentative Nuclide Identification An
Page 55 and 56: correction uses LabSOCS technology
Page 57 and 58: 4 Results, Validations and Discussi
Page 59 and 60: assumed to be constant for detector
Page 61 and 62: 4.2.3 Geometry Description The prop
Page 63 and 64: Table 4.4- Cascade correction facto
Page 65 and 66: Table 4.6- Cascade correction facto
Page 67 and 68: Figure 4.8 Comparison between the f
Page 69 and 70: 4.4 Validations and Discussion To v
Page 71 and 72: 0.900 0.850 0.800 0.750 0.700 0.650
Page 73 and 74: The sediment sample obtained from B
Page 75 and 76: Appendix A Detector 3: Marinelli be
Page 77 and 78: Detector 3: Pellets (1g/cm 3 ) 5 mm
Page 79 and 80: Nuclide Energy (keV) Detector 4: Ma
Page 81 and 82: Nuclide Energy (keV) Detector 4: Pe
Page 83 and 84: Detector 5: Marinelli beaker 0.5 L
Page 85 and 86: Detector 5: Pellets (1g/cm 3 ) Nucl
Page 87 and 88: Detector 6: Marinelli beaker Nuclid
Page 89 and 90: Detector 6: Pellets (1g/cm 3 ) 5 mm
Page 91 and 92: References [1] Radiation Detection

True Coincidence Summing Correction in Gamma Spectroscopy

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